A picture mapping system comprises a vehicle adapted to travel on an agricultural field; a camera mounted on the vehicle for continuously taking pictures of various portions of the agriculture field; a computer mounted on the vehicle for receiving and processing pictures taken by the camera; and GPS receiver means for receiving information signals transmitted from GPS satellites and/or GPS base stations. In particular, the camera is moved continuously by the vehicle travelling on the field, the pictures taken by the camera are continuously fed into the computer, positional information signals transmitted from GPS satellites and/or GPS base stations are also fed to the computer to determine the positions and the orientations of various pictures taken by the camera device, thereby synthesizing together the pictures on the display of the computer to obtain an overall picture representing the entire field.